Low-glycemic foods make their way into the U.S. market
The diet, based on stabilizing blood sugar levels, may help diabetics but its effect on weight loss is harder to determine.
Add one more label to the list consumers are increasingly being asked to parse: This one declares food items as "low glycemic," and refers to a food's effects on blood sugar levels. Low-glycemic diets have become popular in England and Australia, based on studies that suggest they could help manage diabetes and prevent heart disease and obesity, and they're now making headway here in the U.S.
The idea that a low-glycemic diet could improve health -- namely by stabilizing blood sugar and thus preventing overeating -- originated with researchers at the University of Toronto in the 1980s and has been most extensively developed (and promoted) by scientists at the University of Sydney in Australia.
The thinking behind the diet is easily summarized: different carbohydrates are metabolized differently in the human body. Some are digested slowly, causing relatively modest, gradual changes in blood sugar levels. Others, meanwhile, are quickly digested and cause blood sugar to peak and plummet rapidly and dramatically after a meal -- and hunger to set in again quickly.
About a decade ago, several small studies suggested that a diet of mostly low-glycemic foods might help with weight loss. In one study, pregnant women on high-glycemic diets gained more weight by the time they gave birth than women who ate low-glycemic diets. In another, obese women on a low-glycemic diet lost more weight than those on a high-glycemic diet; a separate study of obese children produced similar findings. In a larger study, of men, a high-glycemic diet was associated with being bigger around the middle.
Such findings helped inspire dozens of low-glycemic diet books and cookbooks as well as a certification process that has put "low glycemic" labels on a handful of foods in the U.S., including Uncle Sam Cereal, Ezekiel Sprouted 100% Whole Grain Bread and Silk Organic Soymilk.
The low-glycemic label indicates that a food ranks between 1 and 55 on the glycemic scale. The scale assigns foods a ranking of 0 to 100 based on how much, and how quickly, they cause blood sugar to rise and fall: zero for meat, eggs and most vegetables; around 10 for whole milk and chickpeas and other legumes; and as high as 100 for highly processed baked goods such as doughnuts, croissants and pancakes. A food's glycemic-index ranking reflects, among other things, the type of starch it contains, how much fat and fiber is in it, and how processed it is. A low-glycemic food is typically high in fiber, low in fat, and not processed.
